This request for an ADAMHA Research Scientist Development Award is to support research on the mechanisms of spatial perception in the sonar of bats. The general aim is to determine the perceptual events which occur during the interception of flying insects by bats and to identify the role of neural spatial maps located in the auditory system for mediating aspects of perception of targets. Behavioral experiments will measure the accuracy with which bats track sonar targets with the aim of the head. They will exploit the bat's head-aim reaction as an index of target selection, echo signal-processing, and decision-making by the bat. Other experiments will measure the masking effect of one echo's presence on detection of another echo, as a means of directly studying the function of the neural map of range in the bat's auditory cortex. Physiological experiments will measure the accuracy of coding of echo delay in the auditory nerve and the display of target range in the auditory cortex to gather data for integration with behavioral data. Lesion experiments will determine the relative importance of auditory cortical maps of target range for tracking targets and for fine range resolution.